JPH08229862A - Robot device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the wiring of a power cable, to reduce the radiation of electromagnetic wave, and to promote the cooling of electronic components by arranging drive related to drive means of a manipulator on the manipulator adjacent to the drive means. SOLUTION: A robot device is so formed that respective drive means 1a-1f having respective DC motors 2a-2f and respective reducing gears 3a-3f are arranged in a manipulator. In this case, the respective drive means 1a-1f are related to respective drives 7a-7f attached to the robot. The respective drives 7a-7f are connected to a common single rectifier 6. That is to say, for example, a double-conductor power cable is used common for the respective drives 7a-7f to feed DC. A short three-conductor power cable is connected between the respective DC motors 2a-2f and the respective drives 7a-7f to reduce the troublesome radiation of the electromagnetic wave. This device can also reduce the number of power cables and efficiently cool the respective drives 7a-7f.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manipulator including a plurality of driving means for driving an operating mechanism of a manipulator, each driving means including at least one electric drive motor, and a rectifier and each driving means. The present invention relates to a robot apparatus including a control device for controlling and driving a driving means of a manipulator including a driving device provided.

[0002]

2. Description of the Related Art A manipulator, for example, an industrial robot, has a base rotatably mounted on legs fixed to a base plate, the base supporting a first robot arm rotatable with respect to the base. To do. A second robot arm is rotatably supported at the outer end of this arm. This second arm is rotatable about its own longitudinal axis and at its outer end carries a robot hand which is equipped with a tool attachment device and is rotatable in two degrees of freedom with respect to this second arm. A driving means is provided on each axis for operating the robot arm and the hand. Such drive means each include a motor, for example an inverter-fed synchronous motor with permanent magnets in the rotor, and a speed reducer with a high reduction ratio.

The power supply and control of an industrial robot of the type described above is carried out via a control device which comprises a rectifier and a drive device provided for each drive unit. A rectifier converts the three-phase line voltage into direct current and supplies it to the drive. The drive unit is controlled by a signal from the control unit, which converts this direct current into a variable alternating current for driving the drive motor of the robot. This variable AC
It is preferably in the frequency range 0 to 400 Hz. This alternating current is created by chopping the direct current, thereby creating a pulse train of pulses of variable length and polarity, the purpose of this pulse train is to mimic a sinusoidal alternating current. During such conversion from DC to AC by so-called chopping, high frequency (MHz)
Transient current is generated and is superimposed on the fundamental frequency. These transient currents cause the cable to radiate electromagnetic waves, which can interfere with other equipment.

The principle of a drive system for an industrial robot according to the prior art is shown in a circuit diagram in FIG. DC motors 2a to 2f of their own and reduction gears 3a to 3f of their own
Six driving means 1a to 1f including the above are arranged in the manipulator. The motor 2 is each connected to another drive device 5a-5f arranged in the control cabinet by a long conductor. The drive 5 is whose task is to convert direct current into controllable variable alternating current, which is supplied with direct current from a rectifier 6 which is common to all drives and which is arranged in the control cabinet.

The control device provided with the rectifier and the drive device is usually housed in a control cabinet arranged outside the operating range of the robot. To drive the robot
A multi-conductor cable with a large number of conductors required for each drive unit is provided between the control cabinet and the robot. This cable is connected to the leg of the robot and branches from this point to another drive means, which is usually located on the platform and on the second arm. Six AC motors each require three conductors, which means that the cable contains 18 conductors. One problem with such power transfer is that the total length of the wire is quite long and therefore expensive.
Another problem is that it increases the emission of high frequency electromagnetic waves, which also increases the risk of interference.

[0006] These drive devices generate strong heat when loaded. Each of these drives contains a large number of electronic components, which can become damaged if the temperature is too high. Therefore, these drives must be cooled. An additional problem with placing these drives in a cabinet is that the cooling system must be located in the cabinet.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to obtain a power supply system for an industrial robot, which eliminates the above-mentioned drawbacks. This power supply system limits the emission of unwanted electromagnetic waves and reduces the amount of cables. It also efficiently cools these drives.

[0008]

This object is achieved by placing these drives on a robot,
In that case it is preferable to place them close to each of the individual drive means. These drives are attached to the robot so that the heat generated by the drives is diverted to the robot structure and transferred to the ambient air by convection. These drives on the robot are supplied with direct current from the rectifier in the control cabinet through only one common power cable. Alternatively, the rectifier may be placed on the robot, in which case the alternating current supply from the three-phase network can be connected directly to the robot. The power cable arranged between the drive and the drive means becomes extremely short, which significantly limits the emission of unwanted electromagnetic waves.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail by describing an embodiment with reference to the accompanying drawings.

The circuit diagram according to FIG. 2 shows a drive system for an industrial robot according to the invention. Motor 2 each
And six drive means 1a-1f shown by FIG. 1 including a speed reducer 3 are respectively associated with the drive devices 7a-7f attached to this robot. The rectifier 6, which is common to all these drives, is arranged in the control cabinet, so that power cables with only two cores jointly supply direct current to these drives. A short three-core power cable is connected only between the motor and the drive for each drive shaft, so that the emission of unwanted electromagnetic waves is greatly reduced. The rectifier may likewise be placed on the robot, in which case the main cable can be connected directly there.

The drive 7 does the same work as the known drive 5 and is attached to the robot in order to obtain efficient cooling due to good heat transfer to and from the robot structure. The low operating temperature of these drives makes it possible to choose space-saving electrical components, so that the space required to house these drives is kept small compared to known drives. be able to. Due to the selection of suitable components and the absence of cooling flanges, the space for accommodating this drive can be approximately 60 × 60 × 40 mm ³ .

The industrial robot shown in FIG. 3 has a pedestal 10 rotatably supported on a robot leg 11 fixed to a mounting base, and the pedestal 10 has driving means (not shown) arranged thereon. Can be swung around the vertical axis A with the help of The first robot arm 12 is rotatably supported on the base about the axis B and is rotatable with the base 10.
The balance is maintained by two balance springs 13a and 13b fixed to the upper end of the arm 12 in an articulated manner. The lower end of the first arm 12 is connected to the base 10 and includes a driving means 1b including a motor (not shown) and a speed reducer 3b.
And a drive device (not shown) is attached to the speed reducer. A second robot arm 14 is supported on the upper end of the arm 12 so as to be rotatable about the axis C. The rotation of the arm 14 is performed by a parallel link 15, and the lower end of the link is connected to this stand and to a driving means 1c including a motor 2c and a speed reducer 3c, and the speed reducer is connected to a drive device 7c. Installed.

The second robot arm 14 has a rear portion 14a rotatable about an axis C and a tubular front portion 14b supported on the rear portion and rotatable about the longitudinal axis of the arm.
The outer end of the arm front consists of a wrist 16 rotatable about an axis E and a tool attachment device in the form of a rotary disc 17 rotatable about a longitudinal axis F of the wrist 16. In order to rotate these robot parts 14b, 16 and 17, three driving means are provided on the rear part 14 of the second robot arm.
It is located at a. The drive means arranged on the second robot arm 14 includes a motor and a speed reducer,
In addition, only a motor 2d, a speed reducer 3d and a driving device 7d which include a driving device attached to this driving means but are provided for driving the arm 14b around the axis D are shown in the drawing.

The drive device 7c arranged to drive the first arm 12 around the axis B is attached to the speed reducer 3c provided to operate it. By selecting this position,
Not only the heat dissipation of the robot structure but also the thermal conductivity of the oil enclosed in the reduction gear housing can be utilized. Thus, the heat generated in the drive can be quickly transferred to the entire limit surface of the reducer housing. From the envelope surface of this reducer housing, heat is transferred to ambient air by convection.

Since the driving means arranged at the rear portion 14a of the second arm has a small horsepower, the heat generated by the associated driving device is small. The drive device 7d adapted to drive the front part of the second arm 14 about the axis D is directly attached to the motor 2d adapted to operate. Sufficient heat dissipation is provided by transferring heat to the robot structure through the motor casing so that excess heat is convectively transferred from both the motor casing and the robot structure to the ambient air.

[0016]

A beneficial improvement of the present invention is to replace the common rectifier with a small rectifier provided individually or in groups of drives. These small rectifiers are placed adjacent to the drive. Such positioning can also allow the rectifier to be efficiently cooled through the robot structure.

[Brief description of drawings]

FIG. 1 shows a drive system according to the prior art.

FIG. 2 shows a drive system according to the invention.

FIG. 3 shows an industrial robot according to the present invention.

[Explanation of reference numerals] 1 drive means 2 drive motor 3 speed reducer 6 rectifier 7 drive device

Claims (4)

[Claims] 1. A control device comprising a manipulator provided with a plurality of drive means (1) for driving an operating mechanism of a manipulator, each drive means (1) having at least one electric drive motor (2). At least one rectifier (6) and a drive (7) for controlling and driving the drive means of the manipulator in a robot apparatus, at least one of which is associated with the drive means (1) A robot apparatus, wherein one driving device (7) is arranged on the manipulator adjacent to the driving means. 2. The robot apparatus according to claim 1, wherein:
A robot apparatus characterized in that at least one rectifier (6) is arranged on a manipulator. 3. Robotic device according to claim 1 or 2, characterized in that at least one drive (7) is attached to the manipulator in a manner adapted to dissipate heat to the manipulator structure. Characteristic robot device. 4. A robot apparatus according to any one of claims 1 to 3, wherein at least one drive means (1) comprises a speed reducer (3) coupled to a drive motor, Robot device, characterized in that the drive device (7) is mounted on a speed reducer housing surrounding the speed reducer (3) in order to dissipate heat.